Packet switched network (PSN) aggregation platforms are operable to aggregate Ethernet, Internet protocol (IP), multi-protocol label switching (MPLS), asynchronous transfer mode (ATM), frame relay, and time division multiplexing (TDM) onto Ethernet and IP/MPLS-based architectures. In one application, a PSN aggregation platform can be used to aggregate data from multiple digital line subscriber loop access multiplexer (DSLAM) end customers to a single broadband remote access server (BRAS).
PSN aggregation such as, for example, digital subscriber loop (DSL) aggregation, broadband cable Internet aggregation, and passive optical network (PON) aggregation, is typically handled via either connection-oriented or connection-less aggregation techniques. Examples of connection-oriented aggregation techniques include asynchronous transfer mode (ATM) cross-connect, virtual local area network (VLAN) cross-connect, and frame relay cross-connect. Examples of connection-less aggregation techniques include IEEE 802.1 d/802.1 q Ethernet media access control (MAC) bridging.
Both connection-oriented and connection-less aggregation techniques have relative strengths and weaknesses. Advantageously, connection-oriented aggregation techniques maintain per subscriber visibility, include a well-understood per-subscriber subscription model, provide enhanced security, and allow for layer 2 protocol internetworking such as ATM to Ethernet. Conversely, connection-oriented techniques require a large amount of provisioning and may be limited with respect to the number of connections, especially for Ethernet VLANs. Advantageously, connection-less techniques provide for a simple port-level provisioning model. Conversely, connection-less techniques do not maintain per-subscriber visibility, provide for simple layer 2 protocol internetworking, or provide for strong security.
Existing client devices (e.g. DSLAMs) typically utilize ATM to connect to an aggregation platform. For example, a multi-service switch (MSS) can be used as an aggregation platform. Multi-service switches interface from the customer service area to a service provider's network. A typical MSS includes both an ATM and an MPLS control plane. Further, a MSS includes multi-service interfaces such as OC-48c/OC-12c/OC-3c ATM and packet-over SONET (POS), ATM interfaces such as DS-3, E3, OC-3, DS-1, etc., frame relay/IP interfaces such as OC-3, DS-3, etc., and Ethernet interfaces such as 10/100 BaseT and gigabit Ethernet.
In typical deployments of MSS as aggregation platforms, client devices connect through ATM interfaces to the MSS. The MSS aggregates the clients onto a single port which is connected to an access switch. For example, the client devices can include DSLAMs connected by ATM to the MSS and the access switch can include a BRAS connected to the MSS by ATM or Ethernet. Typically, existing access switch and client devices both connect to the MSS through ATM. However, service providers are migrating to Ethernet to provide lower cost and more flexibility than ATM.
The migration to Ethernet requires the aggregation platform (e.g. MSS) to aggregate ATM attached client devices to the Ethernet attached access switch. In particular, one technique to migrate from ATM aggregation to Ethernet aggregation is to replace the connection between the aggregation platform and the access switch from ATM to Ethernet while leaving the connection between the client devices and the aggregation device as ATM. Disadvantageously, most of the current Ethernet-attached access switches are incapable of terminating a sufficient number of VLAN IDs to efficiently and economically utilize a pure connection-oriented aggregation technique. Further, this allows for client-to-client communications, which further complicates the provisioning and functionality in a pure connection-less environment. Client-to-client communications also introduce additional security concerns.
Additionally, since most client devices utilize ATM to connect to aggregation platforms, it is impractical to utilize a pure connection-less aggregation technique because aggregation platforms are incapable of terminating very large quantities of ATM virtual circuits (VCs) in order to treat each as a virtual Ethernet bridge port. Furthermore, existing aggregation platforms typical utilize ATM switching capabilities that do not include frame reassembly, i.e. aggregation platforms can only switch ATM at the cell layer.
Thus, methods and systems are needed to assist in migrating existing connection-oriented aggregation platforms to connection-less aggregation techniques and to overcome the limitations of pure connection-oriented aggregation techniques by combining connection-oriented and connection-less aggregation techniques.